Types of Broaching Machines
Broaching machines are used to create a uniform width of cut across the top surface of the material being processed. These machines have been around since the early 1900s and were originally designed to make flat surfaces on metal parts. Today, they are still widely used in many industries, including woodworking, furniture manufacturing, and stone cutting. There are three types of broaching machines; horizontal, vertical, and continuous.
Horizontal broaching machines
In this machine, the broach moves in a horizontal direction. A pull-type broach is used. The pull-type broach removes metal when it is pulled through the workpiece. Internal and external broaching are done on this machine. But the horizontal broaching machine is mainly used for internal broaching.
The machine has a base or bed. The base is of box-type construction. The length of the base is slightly longer than the length of the broaching stroke. The front of the machine has a vertical face. An adapter is fitted to this vertical face. The workpiece is located in the adapter. The small end of the broach is inserted through the hole of the workpiece. The small end is connected to the pulling head, and the other end of the broach is supported by the guide.
The pulling head pulls the broach. Normally the pulling head is driven by a hydraulic drive.
When the broach is pulled, it cuts the metal. After the cutting stroke, the pulling head returns to the original position. The broach end is separated from the pulling head. The machined workpiece is unloaded.
This machine broaches keyways, splines, slots, round holes, and other internal contours.
Horizontal broaching machines are used to produce a flat surface on a workpiece. A typical horizontal broaching machine consists of a rotating head with a series of blades mounted at different angles. As the head rotates, the blades move across the surface of the material, producing a flat surface. Horizontal broaching machines are often used to smooth out rough edges on wood products, remove burrs from metal objects, and polish plastic parts.
Vertical broaching machines
In a vertical broaching machine, the broach moves in a vertical direction. A push-type broach is commonly used. The broach is fitted to a slide. The slide moves vertically along the guideways of the column.
Vertical broaching machines are similar to horizontal broaching machines except that the blade set is angled downward instead of horizontally. This type of machine is commonly used to produce a curved edge on a piece of wood or metal.
The movement of the slide is obtained through a hydraulic drive. The workpiece is held in a fixture. The fixture is clamped to the worktable. The left side view of the broach is shown in the figure. The broach does not have teeth throughout its entire width. The broach does not have teeth that are made up of three segments: A, B, and C. Teeth on segment A cut first on the central portion of the workpiece. This method of broaching is known as progress broaching.” If the width of the workpiece is smaller, a single-piece broach is sufficient.
Continuous broaching machines
Continuous broaching machines are used for the mass production of small parts.
Horizontal continuous broaching machines
The machine has two rotating drums. They are connected by an endless chain. Drive is given to one drum. There are fixtures mounted on the endless chain throughout its length. The workpieces are loaded onto the fixtures from one end. The broach is fitted horizontally into the frame of the machine. The workpiece moves under the broach. The chain, when it comes under broach, slides over the rigid support. This gives rigid support to the workpiece when broaching takes place. The workpiece is unloaded at the other end.
The rotary continuous broaching machines
Small workpieces are fitted to a rotating table with the help of a fixture. Broaches are fitted to a stationary broach holder which is placed at the center of the rotary table. There are three broaches. The table rotates continuously. The workpiece moves past the broaches. The third broach is a finishing broach. The other broaches are for rough cutting. After the workpieces leave the finishing broach, they are unloaded. New workpieces are loaded to the fixture. Loading and unloading are done without stopping the rotary table.
